This invention relates to a portable testing device for use in monitoring the communication line activity in a system including a host terminal and a plurality of secondary terminals and for performing turn-around functions with regard to selected terminals in the system.
When installing systems including a host terminal and a plurality of secondary terminals which are all interconnected by a communication line, it is necessary to monitor the transmitting by the host terminal and the secondary terminals in order to install the system properly. It is also necessary to single out the host terminal or the individual secondary terminals to monitor or check the selected terminal for turn-around functions. These monitoring activities are also performed on installed systems when maintenance and repairs are necessary. In such systems, a small, portable device would be extremely useful in performing the monitoring activities mentioned.